How to get on T-Mobile’s super-fast 150Mbps 20+20 LTE bandwagon

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Over Thanksgiving week, T-Mobile quietly launched an upgraded version of its LTE network in Dallas. This network is capable of speeds beyond what most current LTE devices are capable of. With this deployment, T-Mobile is demonstrating its intent to deploy the fastest and largest capacity network it possibly can.

From the very beginning, T-Mobile’s approach to LTE was a story of repurposing already-used spectrum. When the deal for AT&T to acquire T-Mobile failed in 2011, T-Mobile received a package of AWS spectrum that enabled T-Mobile to deploy LTE while retaining its UMTS HSPA+ operations on AWS too. Prior to that, T-Mobile would have to shut down its HSPA+ network on AWS if it wanted to deploy LTE on AWS.

Late last year, T-Mobile announced that it intended to acquire MetroPCS, and completed the acquisition on May 1. Shortly after, T-Mobile expanded MetroPCS to 15 more markets, and again 15 more a few weeks ago. In these markets and the original 15 markets, T-Mobile has replaced MetroPCS’ lineup of CDMA/LTE devices entirely with GSM/HSPA+/LTE ones that rely on the T-Mobile network.

As part of the shift to GSM/HSPA+/LTE for MetroPCS, T-Mobile shut down the MetroPCS LTE network, reshuffled spectrum allocations for GSM, HSPA+, CDMA, and LTE, and relaunched the LTE network with the combined spectrum of T-Mobile and MetroPCS. To fill in the gaps in areas not covered by MetroPCS spectrum, T-Mobile has been participating in spectrum license swaps and acquisitions to reach the goal of supporting the 20+20 MHz (40MHz) LTE carrier size. To enable this carrier size, T-Mobile must align its AWS spectrum assets such that it has a contiguous 20+20 MHz spectrum block in the band.

T-Mobile has said that it will bring 40MHz LTE to 90% of the top 25 markets by the end of 2015, which means that 23 of the 25 most populous cities in the country will have it. These 40MHz LTE zones will support full Category 4 speeds, which top out at 150Mbps on the downlink and 51Mbps on the uplink. However, it appears that T-Mobile may not be able to fulfill that promise with the assets it has now.

MetroPCS CDMA markets

Of the original 14 MetroPCS markets, 10 are in the top 25. These markets are:

New York City, NY

Los Angeles, CA

Philadelphia, PA

Detroit, MI

Boston, MA

San Francisco, CA

Dallas, TX

Miami, FL

Atlanta, GA

Tampa, FL

New York City and Boston have enough spectrum to support 40MHz LTE and HSPA+ on AWS, as well as HSPA+ and GSM on PCS. However, MetroPCS has 10MHz allocated for CDMA2000 service on AWS currently, so these markets will not be able to utilize more than 30MHz for LTE. To move to 40MHz LTE, T-Mobile needs MetroPCS customers to abandon CDMA devices right away, so the spectrum can be repurposed.

In Philadelphia and Miami, there is no way to have 40MHz LTE with the current spectrum holdings that T-Mobile has. Spectrum acquisitions will be required to get that far. LTE-Advanced carrier aggregation with another band is another option, but the performance from carrier aggregation is slightly worse than just using a larger single carrier. This is because there is a greater portion of the spectrum being used for carrier overhead when aggregating separate blocks of spectrum. It’ll be close, but not quite the same.

T-Mobile and MetroPCS bandwidth allocations in Dallas

In the remaining MetroPCS markets, T-Mobile can move to 40MHz LTE now and retain HSPA+, CDMA2000, and GSM. Dallas is one such market where it has already started showing up, with around 100 sites in north Dallas reconfigured to offer 40MHz LTE, according to T-Mobile COO Jim Alling at the UBS Global Media and Communications Conference on Wednesday. 40MHz LTE coverage will continue to grow in Dallas and appear in other markets as T-Mobile prepares the network for it.

T-Mobile GSM markets

The remaining 15 markets are T-Mobile GSM/UMTS/LTE only markets, and they are:

Chicago, IL

Washington, DC

Houston, TX

St. Louis, MO

Pittsburgh, PA

Baltimore, MD

Minneapolis, MN

Cleveland, OH

San Diego, CA

Denver, CO

Seattle, WA

Milwaukee, WI

Cincinnati, OH

Kansas City, KS-MO

Buffalo, NY

Chicago, DC, St. Louis, Pittsburgh, Baltimore, Milwaukee, Cincinnati, and Kansas City cannot support 40MHz LTE with the current spectrum holdings. Some of these markets are are so starved (like Cincinnati), that AWS HSPA+ has to be removed to offer AWS LTE. Given the large legacy base of devices that support only AWS HSPA+, AWS HSPA+ cannot be decommissioned just yet, so either more AWS spectrum is needed for LTE or LTE needs to be deployed on another band.

Houston, Minneapolis, Cleveland, San Diego, and Buffalo have enough spectrum to support 40MHz LTE with the current spectrum holdings. However, these markets will be limited to 30MHz LTE for some time because T-Mobile needs to support older HSPA+ devices that support only the AWS band. As T-Mobile subscribers adopt newer devices that support PCS and AWS for HSPA+, the necessity for AWS HSPA+ weakens.

Denver is in the strange situation of having enough AWS spectrum, but it isn’t lined up to be usable for 40MHz LTE. T-Mobile needs to swap one of its AWS licenses for Verizon Wireless’ AWS license to enable 40MHz LTE. Even after the swap, it will be in the situation that other 40MHz AWS markets are in, for the time being.

In Seattle, T-Mobile can move to 40MHz LTE now and retain HSPA+ and GSM.

T-Mobile has a longer way to go for 90% of the top 25 markets

Contrary to the company’s claims, it does not appear to be so easy for T-Mobile to enable 40MHz LTE in 90% of the top 25 markets — 50% is more like it. However, spectrum holdings do not remain static. Carriers always try to get the largest contiguous chunk of any band they will utilize in order to maximize the capacity and speed benefits of using the spectrum. T-Mobile will certainly try to work out deals throughout 2014 to realign its assets to enable those larger channels.

T-Mobile also has the opportunity to pick up more AWS spectrum in the AWS-3 spectrum auction, which will involve spectrum sharing as a way to make it more immediately usable. The auction is expected to take place late next year, and T-Mobile will can use the opportunity to enable 40MHz LTE in markets where it may not be possible in any other way.

However, over 65% of the top 25 markets are capable of 15+15 MHz (30MHz) LTE on AWS now, which still offers substantially higher performance and capacity over the LTE networks of its competitors (who use 5+5 MHz or 10+10 MHz LTE carrier sizes for their LTE networks). Downlink speeds near 100Mbps should still be possible with Category 4 LTE devices on 30MHz LTE. More importantly, this high performance network would be compatible with every single AT&T and T-Mobile LTE device that has been offered, as well as the few AWS LTE devices offered by Verizon Wireless.

Tagged In

Can someone please elaborate on what 150 Mbps on the download link *really* means? I understand it is a mathematical and theoretical maximum speed on low level protocols that are very far from what people in actual scenarios will ever be able to see even with a device that supports that specific LTE technology. It might, just might, be observed in a laboratory environment. Number of concurrent users, distance to station, surrounding buildings, weather and realistic usage scenarios, I’m afraid, will reveal that the actual number will be half that speed or much less in a vast majority of cases. The problem is that the telcos will continue to advertise that people can zip around town at 150 Mbps fooling its customers.

Actually, it’s likely to be less about the airlink and more about the server on the other end. Very few servers can serve up 20MB/sec. You’d be lucky if a server can serve you 3MB/sec (24Mbps).

seakans

TMO already provides speeds in the range of 35-59 Mbps peak in my Root Metrics tests when I’m on LTE 10+10 (todays setup). LTE and HSPA+ are very similar on the downlink but the uplink is where LTE has the upper hand. As for reaching the max theory rate, it also depends on the backhaul on the cell site. You can only go as fast as the backhaul connectivity bottleneck. Most TMO LTE cell sites have GigE backhaul connections from tier 1 providers (depends what provider is servicing the area), dual band antennas, and modernized connections from the base station without excessively long coax lines to remove attenuation degradation from running cables all the way up the tower and back down to the base.

Jonathon McMullan

The 150Mbps is the limit imposed by the modulation strategy. LTE uses 64QAM (as opposed to LTE-A which uses 128QAM) in conjunction with OFDMA to achieve the ‘150MBps’. So yes you are correct that this is the mathematical maximum speed (sorry for all the acronyms, wikipedia them if they aren’t familiar).

Next you subtract off the overhead which deals with FEC (although this little overhead actually increases the throughput by an order of magnitude in everyday scenarios). This part is all done by the modem. So now we subtract off a bit more for the handshaking bit which is done to tell the tower where the packet needs to go next, followed by a bit more handshaking for the operating system/application or whatever to tell the next server where the packet is going/from and you end up with your real world speed. Which is probably like 80-100Mbps on a really good day. Think 50Mbps for the rest of the time.

Of course all of this scales with distance to the tower because the FEC ends up working harder to deal with the lower signal, retransmitting packets, getting stuck waiting in the queue due to traffic, tower allocates smaller channel reducing bandwidth, your neighbour fires up their microwave which modulates your cordless phone and interferes etc etc etc. All modern communication schemes work this way with varying levels of overhead at each level. I’ve simplified a little bit but that’s the general gist of it.

And like Conan mentioned, not many servers can serve up data fast enough to saturate your connection anyway. Its cool for running Speedtest though :-)

magnuslu

Thank you for the elaborations. On top of that, I believe there is an expected degradation of download capability, both theoretical and practical, once the receiving device is in motion which makes the ‘zipping around town’ statement even more incorrect.

Jonathon McMullan

Practically yes. Theoretically, probably not. The fact that the device is moving should have no effect on the download capability unless you are moving at relativistic speeds. Until then you will experience degradation but it will be due to getting further from the tower, buildings reflecting signal and cancelling out parts, someone else’s microwave, driving past a transformer with a short in its windings which emits broad spectrum noise, that kind of stuff. If you phone misses a packet due to the above reasons, your speed drops.

It also happens that certain trees happen to have leaves which are exactly the right length to form an antenna at the right frequency and attenuate the signal.

magnuslu

From what I’ve read, system performance is optimized for low speeds of 0-15 km/h, supported with high performance for 15-120 km/h and supported up to 350 km/h. Unfortunately, I have not been able to find actual figures.

Jonathon McMullan

Assuming those figures are correct (I haven’t read anything similar but its a massive topic), it sounds more like they are designing the system to make handoffs between cells fast enough to drive through the area. Particularly in large cities with high population densities, micro cells are used to limit the number of different channels required by the telco. The power output of each cell is reduced, and the density of cells is increased. Each cell is divided up like an orange and uses a different set of frequencies in each segment. Your phone needs to handoff from each segment as you pass through it and connect to the next one. The handoff uses data and hence your data rate drops.

Each cell can also use TDD as well as FDD so this adds further complexity (LTE is crazy complicated).

That is an interesting paper. I don’t see any correlation between the speed of the test vehicle and a reduction in bandwidth. This test also has the advantage of being within a single cell which is perfect for testing this kind of thing. It definitely looks like the buildings have a large impact on the signal strength and therefore data rate in this particular set of tests.

Techngro

With a title like “How to get on T-Mobile’s super-fast 150Mbps 20+20 LTE bandwagon”, I was expecting more of a tutorial.

Obviously there is more than just the theoretical capacity, amount of users, what they are doing and overall network infrastructure also make a difference.

Back at home my LTE carrier has 40 MHz available and in January when I was waiting for a few days for the fiber to be installed, I tried my HTC One as a 4G/WiFi hotspot. I was surprised that I was getting 100 Mbit/s over it quite easily (50-100 Mbit/s all the time). Nowadays all the three LTE carriers are advertising up to 150 Mbit/s speeds, at the time they had enabled only up to 100 Mbit/s.

gphillimo

I don’t NEED 150 mbps download. It would be nice, but i live in the St. Louis area and T-Mobile has the whole city covered in HSPA+ averaging 15 mbps download, and T-Mobile now has LTE here, which i’ve seen hit over 50 mbps download. I don’t need faster LTE at the sacrifice of hspa+ because during that transition the speeds will drop significantly with everybody congesting the network. I can live with the current LTE i have on T-Mo. Unlimited and it streams netflix with no lags.

Nate Opgenorth

15+15MHz LTE is nothing to complain about….in actual tests I’ve noticed that 15+15 and 20+20 are very similar where as 5+5 or 10+10 just don’t get near it all that often. In my area Verizon has 15+15 on AWS and T-Mobile has 20+20 on AWS and they are very similar but with T-Mobile having the upper hand in metro areas. I assume this is because of less of a network load on T-Mobile. Ah well I love using my T-Mobile SIM to upload and download things super fast and when I hit Manhattan I expect to be testing this allot as well as taking advantage of it for amazing internet use (got a couple of long videos I need to upload :P)

bronxlcswr

I just bought a new Galaxy note 4 and use with tmobile here in the Bronx, NYC. I was absolutely shocked to see my average download speed on ookla speed test is about 60mbs with 27mbs upload. I get as high as 76mbs and the lowest speed so far was never lower than 40mbs. When i used my Note 3 i was averaging in the 30mbs range. Did Tmobile upgrade the NYC area with the new 20×20 spectrum?? Or is the Note 4 equpped with a new chip to get these speeds. I mean this wireless speed is faster than my fios home connection… Anybody know whats going on?? I am not complaining just curious.

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